#include "my_stdio.h"
#include<string.h>
#include<stdlib.h>
#include<sys/stat.h>
#include<sys/types.h>
#include<fcntl.h>
#include<unistd.h>

mFILE *mfopen(const char* filename, const char *mode)
{
    int fd = -1;
    if(strcmp(mode, "r") == 0)
    {
        fd = open(filename, O_RDONLY);
    }
    else if(strcmp(mode, "w") == 0)
    {
        fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
    }
    else if(strcmp(mode, "a") == 0)
    {
        fd = open(filename, O_CREAT | O_WRONLY | O_APPEND, 0666);
    }
    if(fd < 0) return NULL;
    mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
    if(!mf)
    {
        close(fd);
        return NULL;
    }

    mf->flieno = fd;
    mf->flag = FLUSH_LINE;
    mf->size = 0;
    mf->cap = SIZE;

    return mf;
}

void mfflush(mFILE *stream)
{
    if(stream->size > 0)
    {
        //写入内核文件的文件缓冲区中!
        write(stream->flieno, stream->outbuffer,stream->size);
        //刷新到外设
        fsync(stream->flieno);
        stream->size = 0;
    }
}

int mfwrite(const void *ptr, int num, mFILE* stream)
{
    //1. 拷贝
    memcpy(stream->outbuffer + stream->size, ptr, num);
    stream->size += num;

    //2.检测是否要刷新
    if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1] == '\n')
    {
        mfflush(stream);
    }
    return num;
}

void mfclose(mFILE *stream)
{
    if(stream->size > 0)
    {
        mfflush(stream);
    }
    close(stream->flieno);
}
